Kinetics, stages and fracture modes of stress-corrosion cracking in ZK60 and AZ31 alloys

• Published in: Materials letters 2023-03, Vol.334, p.133702, Article 133702
• Main Authors: Merson, E.D., Poluyanov, V.A., Myagkikh, P.N., Merson, D.L., Vinogradov, A.
• Format: Article
• Language: English
• Subjects: Crack growth; Fracture surface; Magnesium alloys; Stress corrosion cracking; Stress intensity factor
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2022.133702

•Fracture mode alternates during stable stress corrosion cracking.•Crack growth rate increases when fracture mode changes from brittle to quasi-brittle.•The change of fracture mode occurs at a characteristic stress intensity factor.•The velocity of stable SCC in alloy ZK60 is higher than in AZ31.•The threshold and critical intensity factors of ZK60 are higher than those of AZ31. The kinetics and fractographic features of stress corrosion cracking (SCC) in ZK60 and AZ31 alloys was investigated. It is established that ZK60 alloy possesses higher SCC resistance and fracture toughness compared to those of AZ31 alloy as is evidenced by the higher threshold stress intensity factors K1SCC and Kc. However, the lower average velocity of the stable SCC is observed in AZ31 alloy than in ZK60 one. Stable SCC occurs in two sub-stages, the first of which is featured by the lower crack growth rate and brittle fracture mode, while the higher crack velocity and quasi-cleavage fracture mode herald the second sub-stage. The crack growth velocities at specific SCC stages as well as stress intensity factor Kf associated with the alternation of the fracture mode are evaluated.